It is simple. I do not deal with them.
If someone says something that seems reasonable, I respond. Sometimes even have back-to-back conversations.
If someone says something that is not true, I simply have fun. By not responding most of the times :)
The truth is, if you truly know yourself, no one can touch you. If you are at peace with who you are, external chaos is merely a chatter. If you are aware of your qualities as well as disadvantages, you have an unfair advantage that most people don’t have. And that’s the most powerful thing.